Piston ring



March 11, 1930. A. w. MORTON 154 332 PISTON RING Filed Dec. 7, 1928 I 5110 8A 15 Q canine STATES- PATENT oFFicE ALLEN w. Mormon, or: summons,MARYLAND, ASSIGNOB m run AMERICAN mcomramr, or nammonn aunt-LAND, Aconrona'non or Patented Mar. 11 1930.

' unnnn' r sron' 311w:

mymma Applicationtled December Thisv invention relates to piston packing20 the gaps in staggered relation; 'and'other detwo resilient elements.

The purpose of the invention is to produce 5 a ring of this generalcharacter which is rectangula r'in cross section so asto be received ina: piston ring groove-of conventional form. L A-' further objectofthe-invention is to insure that onlyone of the ring elements contactsthe cylinder walls,--both elements having portions which contact thesidewalls of the groove.

Further objects of the inventidn have to "rxs'rdn-nma' v 7, 1928. Serial110. 824,481.

' ringelement 7 which hasniariy of the charoutwardly extendingflange 9,which is on the opposite edge from the flange-8 and over- 7 laps thesame. The extremity of one flange seats against the body 'of thecompanion ring, but there is clearance between the extremity of theotherflange and the body of the first ring; The two flanges are prefer-"dowith the production of a uniform expanf" ably of the same thicknessbetween plane sursive tendency thronghout thecircumference \faces, butwhere-extra; outward pressure of of the ringstructure; theproduction ofsati sthe inner ring is desired, the flangeon the factory sealingbetweenthe split ends ofthe inner ring may be increased and that on theouter ring element and between the two asouter ring may be gorrespondingly decreased sembled ring elements; the'maintenance of in thickness.

tails which "will be apparent to those skilled in Figs. 5 and 6 in whichflange 9 contactsthe in the art upon consideration of the followbody ofring 6 and there-is a slight clearance The preferred arrangement is thatshowning detailed description. 1

A preferred embodiment of the invention is illustrated in v which,-- p

.Fig. 1 is a perspective view of the two rin g elements, separated fromeach other.

Fig. -2 is a perspective view of the img structure with the twoelementsassembled and contracted to their miniinum diameter. T Fig. 3 isa transverse section of the ring structure. 7

F fl: is adetail view-showing the ring in a groove in a'pistonandillustrating the allIL- .ing luglor pin which is used in cases where thering is to travel over cylinder ports... L Fig. 5 is an enlarged:fragmentary axlal sec- I tion through a pi ton and cylinder showingcylinder wall, and the joint between the two ,th'e.1 'ing on the uptravel of. the piston,"

construction.

Fig. fieis msimilarview showing the posi- Y tions assumed when the ringmoves down-' has many of the characteristics of an ordinarysnap and aspecially related inner the accompanying drawing, in which'flan I a A aance exists tween body 6'and flange 9. The

between flange 8 and body 7. The alternative arrangement is shown inFigs. 7 and 8 in 8 contacts body 7'and a'clearat theplane surfaces whichbound the ring, as

contradistinguished from the V cylindrical bounding surfaces. The effectof this is that the outer ring element 6 alone contacts the ringelements does not extend to the cylinder contacting surface. I This isan important feature in the reduction of wear both on the cylinder walland. on the ring groove in the piston, as will be explained, and assistsin the securing of a tight seal with the sides B ithe".

pressure groove by the action of the fluid 'whose leakage is resisted.

' The outer ring section 6'is, of course, split i to permit it toexpand, and any type of leakresisting joint might be used. I indicate at11 a known-type of bevel step joint, but contemplate using anyknownjoint. p g

It is necessary that the splits in the two ring sections be staggeredand preferable that they, be displaced '180 from each other.

Staggering reduces the tendeney to leakage and may be arranged togi'veauniform expansive tendency. To maintain the desiredrelation of the ringsections the recess at the side of flange 8 is interrupted for a shortdistance tov leave'the boss (indicated at 12. The, sides of the boss arecurved or filleted to avoid the formation of incipient cracks The endsof the-flange 9 areicut away as indicated at 13,

a to fit approximately the sides of the'boss 12 when the ring is in itsmost contracted position (see Figs. 2 and 4) While it is suflicientmerely to cut away the ends of, the flange 9, '.itsimplifies manufactureto cut awaythe ends of the inner ring. This arrangement gives clearancefor a positioning pin or stud 14,

shown in Fig. 4,3111 the base of the riiig groove.

' This preventstlie rotation of the ring in-the piston and is necessarywhere the ring travels, 5 oveic'ylinder'ports. I f r In order to'controland properlydistribute the expansivetendency of the-inner ring 7, thismaybe hammered or peened on its inner surface, in a manner. wellknownifithe art.

The hammerQmarks, which are variably.

, spaced according toknown practice, are indicatjed, at 15. Equivalentmethods known in the. art,-'sueh as heat treatment while held outof'r'ound, turning the ring out of round, man "sfi ufaeturing from outof round castings, and I the like, may be adopted to secure similar re-A compound ring f scribed. presents to the cylinder wall a prac- 40tically continuous sealing surface. Because of the reverse arrangementsof the two rings.

ther'eis aninhe'rent tendencyto produce an v equalized outward, tendencythroughout the Qircumference'of the compound ring and this I efi'ect canbe enhanced by special treatment of theifnner ring, as suggested.

l The. formation of the lugwhich holds the two ringsin'a definiterelation integral with the ,outer ring, avoids thiefweakning effect ofinserted 'PTIiS' HIId-BBGQIISB' ofit'spurved, or filletedfformprecludesthe formation of in cipient cracks,"such as, are likely'tooccurat sharpcorners. Furthermore,the ring is so designed as torreducethe tendency to wear the plane or side faces of the ring grooves, severewear at such points being} one of the undesirable characteristicsofprior duplex rings.

- At-the present time probably the. largest field for-duplex rings is asreplacement'rin'gs Go in Diesel engines; notably marine-engines.

' The'yyareused rtotake the place ofone-piece' l struction. In Fig. 5theparts are shown poringswhich cannot satisfactorily be replaced withanother one piece ring because of wear iii the ring grooves'and-becauseof the worn I '9 condition re; eylif der and pist'on. It fol- "adverseconditions, being used to;put-off as:

parts, each of which contacted the cylinder" constructed as aboiredelows that a duplex ring normallyencounters long as possible thedayofv-a thorough overhaul. InTselecting such rings engineers customarilyplace the first emphasis in the seal at the'joint of the ring, and nextthey demand a ring which will seal in the groove of the piston. Contraryto the conditions in a new en- *gine, the seal of the ring with thecylinder seat in sooner or'latenand thatduring such' seating the leakageat the joint in the ring and f the leakage through the grooves willgradu- 1 ally increase. This explains the growing use so ofthe-duplex'rin'g, but all prior duplex rings, so far as I am advised,have-consisted ofstwo wall. The effect was to produce ring sectionswhich were so narrow that they were torsionally flexed during'thereciprocations of the piston. causesuneven Twear oi the ring and'rapidwear of the groove.

The characteristic of the present ring in presenting to the cylinderwall a single ring 'wall is generally 'regardedas the least im- 75 iunit. and 'to form thatdunit with a flange I which gives itconsidrabledepth of engagement. with the ring groove, reduces in a marked degreethetendency for torsion a1 flexure to occur with its accompanying wear 1. 5on the ring and groove. It also avoids frail" sections such asare commonin'duplex rings obthe .prior art. The importance bfthi's is accentuatedby themodern tendency, toward very'narrow piston rings, f "I While;rings of. he type above disclosed might be placed in a groove eitherside up,.the

better practice is to" mount the rin s so than,

thprSSliifB-Wli0S leakage is resisted will seat the outer ring againstits broad face."1 This arrangement is shown in Fig. 5 in which thepressure is supposed to act on; piston A in a. downward direction. Insuchcase the outer section 6 will be seated against its broad plane face:at all times in a two stroke cycle 9 engine and-,in a four'stro'kecycleit'willl seated-against the broad plane face'on'the. compression,working and exhaust strokes and against the narrow plane face on onlythe suction stroke. I It! has been explained that only one of theflanges, preferably the flaiige-9,,of thein'nerring, seats. againstthe'body of the-other preferably the outer ring). .Fro'm theoretis calconsiderations one would assume that itn wouldbe better t' have bothflanges seatfb ut the fact is that-in manufacture it ispracti-' 'callyimpossible toaccomplish this result and a tests show that better resultsare secured when only one flange seats. F- Y Figs. ,5 and 6'-illustratethe preferred con- I sitionedas they are at or about the moment of Iignition, at. which time 'the piston A is still moving"upward-relatively to eylinderwallB v rangement, Fig. 7 showing thecondition at modification as to'detail and the scopeof the the ignitionpoint, as in Fig. 5, and Fig. 8 the condition on the'workingstroke'after the gas pressures have penetrated the ring groove;

As suggested the ring is subject "to some invention is defined in theclaims, the description of a speeific embodiment being not intendedtohave a limiting efl'ect.

Vhat is claimed is, 1. A piston ring structurefcomprising two resilientsplit ring elements,- one ring encircling the other 'with their splitsstaggered, the inner rin having an outwardly projecting flange an theouter ringhaving an inwardly projecting flange, said flangesoverlapping, and tone only of said flanges, engaging the body of theother ring. I I I 2; A piston ring structure comprising two resilient'split' ringelem'ents, one ring encir-- cling the other with theirsplits staggered, the

I inner ring having an outwardly projecting flange and the outer ringhaving an inwardly pro ecting flange, said flan es overlapping.

the first named flange having slightly the,

greater radial dimension.

3 A piston ring structure comprising two resillent spht ring elements'of equal thickness between plane surfaces,- one ring encircling theother with'their splits staggered,

the inner ring havingan outwardly projecting flange and the outer ringhaving an inwardly pro ecting flange,

said flanges alone overlapping, and the vflange of one ring only acontacting the body of the other ring.

ness between plane surfaces,

. lapping,

4.1A piston ring structure coniprisin W0 resilient split ring elementsof equal ,t

one ring encirickgap between the ends the inner ring which receives saidstud and said lug.

'6. A" piston ring structure comprising tworesilient split ring elementsof equal thickness'between plane surfaces, one ring encir cling theother with .their splits staggered, the

inner rin having an outwardly projecting flange an the outer ring havingan inwardly projecting flange, said flanges overlapping,

"and only one contacting the body of the other ring, there being a gapbetween the flange ends of the inner ring in the contracted position ofthe ring structure, and a boss on projecting section of'the innerL-shaped ring alone contacts the outer ring.

8. A piston ring structure comprising two resilient split ring elementsof equal dimension between plane surfaces, one ring encircling theother, with their-splits displaced approximately diametrically from geach other, the outer ring having an inwardly projecting flange and theinnerring having an outwardly projecting flange which overlaps theflange on the outer ring, the flange of the inner ring alone contactingthe body of the outer ring, said inner ring having a greater outwardresilient tendency than that of the outer rin In testimony whereof Ihave signed my name to this specification.

' ALLEN W, MORTON.

cling the other with their splits staggered,

, the inner ring having, an outwardly proecting flange and the outer rinhaving an "inwardly projecting flange, said anges overthe flange of onering only contact- ;ing the body of theother ring, there being a gapbetween the ends of the flanges of the in I "ner ring in the contractedposition of the ring structure; andra boss on I substantiallyfilling'said gap.

i ,equal thickness between 5. The combination with a piston having agroove and a studlocated in theibotto'm of said groove, of a piston ringstructure com-' prising two resilient split ring elements'of planesurfaces, one, ring encircling the other with their splits staggered,the inner ring having an outwardthe outer ring -ly projecting flange andthe outer ring having .an inwardly projecting flange, said flangesoverlapping,there being a lug at the side ofthe flange on the outer ringand a

